Coral polyps are a class of marine invertebrates belonging to the intestinal type. These are colonial or rarely solitary polyps that live in the seas. Currently, two subclasses are distinguished: eight-ray and six-ray coral polyps. The first group includes colonial organisms having 8 feathery tentacles (red coral, sea pen, organ). Polyps of the second group, mostly solitary, have a number of tentacles that is a multiple of six (anemones, stony corals). There are approximately 6,000 species known. coral polyps, common in seas with high salinity in different climatic zones. Most coral polyps live in warm tropical seas with a water temperature of at least 20 degrees, at a depth of up to 20 m, provided there is an abundance of food - plankton.

The most primitive firms have been found in strata dating back to the Cambrian period. At first mesozoic era on Earth, subclasses of eight-ray and six-ray coral polyps appeared.

Hydroid coral polyps differ from other representatives of the class in a more complex structure, the presence of a pharyngeal tube located inside the body and ending in a mouth opening, the division of the body by radial partitions into separate cavities, and a more perfect structure of the body as a whole. The vast majority of coral polyps form colonies, representatives rare species single.

These organisms have a typical cylindrical body shape. At the rear end of the body there is a flat round surface, the so-called "sole", with which polyps are attached to objects under water. Stands out at the forefront mouth opening with one or more rows of tentacles around the circumference. The mouth opening opens into a wide pharyngeal tube - a kind of stomach. The structure of the stomach wall is three-layer, similar in structure to the wall of the animal's body. Undigested food debris is expelled external environment through the mouth. The gastric cavity is multi-chamber due to its division into parts by radial partitions. During the day, polyps squeeze their tentacles, and at night they straighten and catch prey - various smallest animals of plankton. Single polyps large sizes they can also catch larger animals - shellfish, fish.

Some species of coral polyps have stinging organs in the form of filaments that perform a protective function, which, in case of danger, are thrown out through the mouth opening or through holes in the wall of the polyp's body. In the structure of the body wall of a coral polyp, three layers are distinguished - ectoderm, mesoderm and endoderm. The ectoderm covers the outside of the entire body of the individual and is the inner lining of the pharyngeal tube. The ectoderm consists of three layers: epithelial, nervous and muscular. Many representatives of this group of animals have a calcareous skeleton of ectodermal origin, giving rise to horny and calcareous deposits that form a polyp forest. The mesoderm is a gelatinous substance that fills the cavities of coral polyps and includes spindle-shaped or star-shaped cells and fibers. In the mesoderm, calcareous bodies may also be present, which sometimes join together to form a dense calcareous mass. The endoderm is divided into the same three layers as the ectoderm, but the structure of the layers of the ectoderm and endoderm is different. These organisms do not have special sense organs.

Reproduction of coral polyps is carried out both asexually and sexually. asexual reproduction occurs by budding. The development of germ cells occurs in the endoderm of the mesenteries. Young organisms leave the mother at the planula stage, floating in the water column for a certain time, and then attaching to the bottom during the transformation into an adult.

Extensive colonies of coral polyps are formed with incomplete budding. Corals in the seas are motionless and outwardly look like branches of plants. But each coral branch is nothing but accumulations of small animals - coral polyps. These clusters are called colonies. Coral "grows" with the birth of young polyps. If environmental conditions are favorable, coral growth is about 1 cm per year. With the growth of colonies of coral polyps in the tropics, barrier reefs, atolls ( coral islands). The vast majority of coral polyps in the reefs are six-pointed corals. Due to their calcareous skeleton, they are widely used as building material. The Mediterranean Sea is home to red and black octagonal corals whose skeletons are highly valued as ornaments.

Coral polyps are a class of marine invertebrates belonging to the intestinal type. These are colonial or rarely solitary polyps that live in the seas. Currently, two subclasses are distinguished: eight-ray and six-ray coral polyps. The first group includes colonial organisms with 8 feathery tentacles (red coral, sea pen, organ). Polyps of the second group, mostly solitary, have a number of tentacles that is a multiple of six (anemones, stony corals). In total, about six thousand species of coral polyps are known, distributed in seas with high salinity in different climatic zones. Most coral polyps live in warm tropical seas with a water temperature of at least 20 degrees, at a depth of up to 20 m, provided there is an abundance of food - plankton.

The most primitive firms of coral polyps have been found in beds dating back to the Cambrian period. Since the beginning of the Mesozoic era, subclasses of eight-ray and six-ray coral polyps have appeared on Earth.

Hydroid coral polyps differ from other representatives of the class in a more complex structure, the presence of a pharyngeal tube located inside the body and ending in a mouth opening, the division of the body by radial partitions into separate cavities, and a more perfect structure of the body as a whole. The vast majority of coral polyps form colonies, representatives of rare species are solitary.

These organisms have a typical cylindrical body shape. At the rear end of the body there is a flat round surface, the so-called "sole", with which polyps are attached to objects under water. An oral opening with one or several rows of tentacles along the circumference stands out on the anterior margin. The mouth opening opens into a wide pharyngeal tube - a kind of stomach. The structure of the stomach wall is three-layer, similar in structure to the wall of the animal's body. Undigested food residues are removed outside into the external environment through the mouth. The gastric cavity is multi-chamber due to its division into parts by radial partitions. During the day, polyps squeeze their tentacles, and at night they straighten and catch prey - various smallest animals of plankton. Single polyps of large sizes can also catch larger animals - shellfish, fish.

Some species of coral polyps have stinging organs in the form of filaments that perform a protective function, which, in case of danger, are thrown out through the mouth opening or through holes in the wall of the polyp's body. In the structure of the body wall of the coral polyp, three layers are distinguished - ectoderm y, mesoderm y and endoderm y. Ectoderm a covers the outside of the entire body of the individual and is the inner lining of the pharyngeal tube. Ectoderm A consists of three layers: epithelial, nervous and muscular. Many representatives of this group of animals have a calcareous skeleton of ectodermal origin, giving rise to horny and calcareous deposits that form a polyp forest. Mesoderm A is a gelatinous substance that fills the cavities of coral polyps and includes spindle-shaped or star-shaped cells and fibers. In the mesoderm, calcareous bodies may also be present, which sometimes join together to form a dense calcareous mass. Endoderm A divided into the same three layers as the ectoderm A , but the structure of the ectoderm layers s and endoderm are different. These organisms do not have special sense organs.

Reproduction of coral polyps is carried out both asexually and sexually. Asexual reproduction occurs by budding. The development of germ cells occurs in the endoderm of the mesenteries. Young organisms leave the mother at the planula stage, floating in the water column for a certain time, and then attaching to the bottom during the transformation into an adult.

To date, about 5,000 species of corals are known. They resemble something like a tree, bush, carpet, ball, etc. Popularity is due to the fact that they are very similar to gems. But most people don't even know if it's an animal or a plant? We will answer this question in this article.

Coral is an animal or a plant

With the naked eye it is very difficult to understand what kind of organisms they are. This is due to several reasons. But it’s worth saying right away that coral is an animal, not a plant. They have a skeleton that can only be felt by touching it. You have probably heard of So, they are made up of millions of dead organisms, which, after death, harden like a stone. If you understand in more detail, then the coral is a huge number of tiny organisms, which together form the structure of the polyp is quite simple. It consists of a cylindrical body with tentacles. Between the latter there is a mouth opening.

Coral sizes and something else

Polyps are quite tiny, their size usually does not exceed a few centimeters. As for the colony that these creatures form, that is a completely different matter. For example, stony coral polyps can reach 40-50 cm in diameter. Separate individuals are interconnected by means of a cenosark. As a result, a single organism is formed. All individuals forage for food together. Larger particles catch particles, small ones participate in reproduction. So we have already figured out what corals are. Is it an animal or a plant? You already know the answer to this question. It is worth noting that the most ancient Coral reefs were created 23 million years ago. This suggests that polyps appeared a very long time ago. As noted above, for the most part, reefs are a large number of dead individuals. The exception is upper layer which has recently formed.

Coral shapes and sizes

You can endlessly talk about the fact that there are a wide variety of colors of polyps. The same applies to their forms. If for the most part corals have the same shape, although there are exceptions, then they form the most impressionable and diverse colonies. This applies not only to shape, but also to color, as well as size. The smallest colonies are no more than a few centimeters long, and the giants of the genus can reach 5-6 meters. As for the form, this is a separate conversation.

Some colonies can be very simple and can be a twig or a hook. Others differ in their complexity. For example, the shape of a shrub or colony that resembles the shape of a tree is not uncommon. One can endlessly wonder how these form something so beautiful and complex. There are representatives that do not grow up, but in breadth. Such colonies resemble mushrooms or small carpets. Are you wondering what an animal or plant eats? Of course, in most cases they catch microorganisms, among which there may be both those and others (plankton).

and habitat

Coloring may be different. But most often you can see brown and red colonies. Somewhat less common are orange. It is even more difficult to find a green, pink or black colony. After all, not every scuba diver has seen blue-violet or bright yellow corals. They are considered very rare and do not live everywhere. As you can see, coral can be of various colors. It's an animal or a plant, you already know, so let's talk about where the colonies live.

The main habitat of corals is tropical and subtropical waters. The fact is that most of the species are thermophilic. But gersemia, one of the subspecies, lives far in the North. Remarkably, all polyps do not survive in fresh water, so absolutely all individuals live in a salty environment. Colonies settle at a shallow depth of up to 50 meters in places with the highest illumination. For corals, it is extremely important that they are constantly in the water, otherwise inevitable death occurs, but some individuals have learned to retain moisture for some time, for example, at low tide. The essence lies in the special form of the polyp, which resembles a shell, where moisture is stored.

A few more features

You must have noticed that the various shapes and colors can be even the simplest coral. Is it an animal or a plant? The answer to this question was given at the beginning of the article. But it is worth noting that if you do not touch the polyp, then it is difficult to understand whether it is alive or not. However, by touch, you can feel the skeleton of the animal. Interestingly, polyps always settle on a hard surface, since silt is not suitable for them. Large colonies can often be observed on long-wrecked ships.

The lifestyle of many species is sedentary. However, some constantly move along the bottom in search of food. By the way, corals can be safely attributed to predators. They go hunting at night. They stick out their tentacles and catch plankton and other organisms in the water. By the way, they do not search during the day due to the fact that the tentacles are very sensitive to ultraviolet radiation, such radiation can burn them. We have already answered your question about whether corals are animals or plants. You can find photos of the most interesting colonies in this article.

Conclusion

Despite their simplicity, polyps surprise with their beauty, which attracts many corals. The sea, especially if it is salty, can always show you the most interesting settlements of these animals. Today, it is very common to deliberately capture entire colonies and make ornaments out of them. And they grow very slowly, about 1-3 centimeters per year. By the way, the growth process largely depends on the illumination and saturation of water with oxygen. It is for this simple reason that this issue comes up more and more often at meetings of researchers and conservationists. For tens of thousands of years, entire reef islands are formed, which are destroyed by man in one day. Well, that's all that can be said about what corals are. Animal or plant? Of course, an animal, because these organisms can grow and combine into entire colonies and eventually build reef islands.

beauty underwater world, its splendor and diversity always amaze nature lovers who go to see marine life. At the heart of this diversity are very unusual inhabitants.

Introducing Interesting Facts about corals

Corals have the most extraordinary color range, which shimmers beautifully in the ocean depths.

In total, there are more than 6 thousand such underwater inhabitants and this is one of the richest varieties of coelenterates.

Corals are quite picky

So, for their growth, they need full-fledged conditions: sufficient salinity of water, transparency, warmth and a lot of food. That is why coral reefs live in the waters of the Pacific and Atlantic oceans.

It is interesting that in the World Ocean the territory of coral reefs has about 27 million square meters. km.

Big barrier reef considered one of the greatest creatures these underwater growths. It extends near Australia.

Lime reserves due to coral reefs are almost inexhaustible

Some areas of such reefs are so large that they can rightfully be called coral islands.

Coral islands have their own life and vegetation. Here you can even find cacti and tall shrubs.

The local population uses corals to make jewelry.

It turns out very beautiful and iridescent products for the summer season.

Corals are also used as a building material, polishing metal surfaces and manufacturing medicines.

If a person is damaged by the coral barrier, then the skin will heal for a very long time. Even suppuration may appear at the site of the wound, regardless of whether the coral is poisonous or not.

Corals have special cages designed to protect themselves.

They are called stinging and release poison at the moment of danger.

The Hindus had a belief that only men should wear red corals, and only women should wear white corals. It was believed that these colors are a kind of symbolism of one and the other sex, and in the case of "wrong wear" each of them acquired the character traits of the opposite. How true this is is unknown.

Today, few men wear coral products. Well, women allow themselves any color scheme, including red. Apparently, it is because of this that emancipation flourishes in our country.

You will find other interesting facts about corals on the Internet.

These are exclusively marine, mostly heat-loving organisms. There are both solitary and colonial forms (the latter more often). There is no medusa form in the development cycle.

Compared with hydroid polyps, they are more complex. A separate coral polyp of the colony outwardly resembles a hydra, but is usually located in the cup of its external skeleton. The complication of their organization consists in the presence of a pharynx, the division of the intestinal cavity into chambers with the help of vertical partitions, which increases the surface of secretion and absorption of food.

Separation of the muscular and epithelial parts of the epithelial-muscular cell and the formation of differentiated muscle tissue are observed.

The nervous system is of a diffuse type, but with a greater concentration of nerve cells at the mouth opening than that of the hydra.

Coral polyps reproduce both asexually and sexually. The gonads develop in the endoderm of the septa of the intestinal cavity.

The fertilized egg begins to split. First, it divides in two, then each of the formed cells, in turn, also divides, and so on. As a result, a large number of small cells are formed, arranged in one layer and looking like a small hollow ball. Following this, part of the cells sinks inward, resulting in a two-layer embryo. From its inner layer, the endoderm is subsequently formed, and from the outer - the ectoderm of the future polyp. The ectoderm is covered with numerous small cilia, with the help of which the embryo acquires the ability to swim; from that moment it turns into a larva, called planula. Planula is unable to feed and reproduce. She swims in the water column for some time, then sits on the bottom and attaches to it with her front end. Shortly thereafter, a mouth opening breaks through at the posterior (now upper) end of the planula and a corolla of tentacles is formed. This is how the first polyp appears. In colonial forms, this polyp soon buds on itself other polyps, which in turn follow, and so on. a colony emerges. When a colony reaches a certain degree of development, its constituent polyps also begin to reproduce sexually, forming eggs. This completes the cycle.

Among solitary soft coral polyps, there are widely known anemones, which for a variety of colors are called sea flowers.

Colonial forms are numerous and varied (ball-shaped, tree-like, etc.). Their skeleton is made up of calcium carbonate. Calcareous skeletons of colonial forms form reefs and oceanic islands - atolls. Organic red skeletonnoble coral used to make jewelry.

Control questions:

What structural features are characteristic of intestinal cavities (for example, hydra)?

How does a hydra eat?

What types of reproduction does hydra have?

Which common features and differences have representatives of the classes Scyphoid and Coral polyps?

How do Scyphoids reproduce?

Coral polyps or marine - living creatures that may not move at all, and if they move, then very little. They live at the bottom of the sea large groups are rarely alone and do not have a backbone.

You can find more precise definition What are polyps, biologists say - these are some forms of aquatic animals that have stopped at a certain stage of development. And at the next stage, a jellyfish is already obtained. Among this class, you can count about 6 thousand species, among them there are even those that do not have a skeleton, which consists only of protein.

If translated literally from Latin the name of coral polyps, it turns out such a funny name - an animal - a flower. It is this name that indicates the shape of the polyps themselves. All of them really resemble a flower, they can be of different diameters, sometimes they reach a diameter of about 60 cm, and the height may well be a meter. Coral polyps can be used as aquarium decorations, and they are also used by jewelers to make jewelry.

Coral grows about one centimeter per year if they grow in comfortable conditions. They grow at great depths, because it is there that a large amount of plankton lives, they feed on it. And large polyps that live alone can eat small fish.

Polyps can reproduce in two ways: the first is the larva, which is obtained from the mating of jellyfish, it settles somewhere and begins to grow. The second is the division of polyps into parts, in other words, sterile reproduction. Jellyfish appear thanks to polyps.

There are certain types of polyps that cannot turn into a jellyfish. Such polyps create coral reefs, they have only a skeleton consisting of lime.

Since it was already mentioned earlier that some polyps do not have a skeleton, anemone belongs to them. She lives alone, can be of impressive size - about one and a half meters. They lead exclusively sedentary image life, while they can also coexist with some species of fish. Very large sea anemones can even feed on fish that are medium in size. They may well move along the bottom due to the fact that they compress and unclench the sole, but very slowly.

In nature, there are not only polyps that do not turn into a jellyfish, since they do not have this stage, but there are also jellyfish that cannot become polyps.

Polyps are very important in environment they clean up sea ​​water from organic particles. Also, coral limestone can be used for construction, but not in all countries. It is coral polyps that take part in the formation of reefs.